# Factoring

• May 16th 2006, 10:21 AM
ferdo
Factoring
Ok, the question we got was to identify and explain one critical error in the factoring example.

this is the example:

X=X

X Exponent 2 = X Exponent 2

X Exponent 2 - X Exponent 2 = X Exponent 2 - X Exponent 2

X(X - X) = (X + X) (X - X)

X(X - X) = (X + X) (X - X)
-------- --------------
(X - X) (X - X)

X = (X + X)
X = 2X
If we let X = 1, then upon substitution we have
(1) = 2(1)
1 = 2

I think the problem lies in line 3 right side, (X + X) (X - X), should it be like the left side X(X - X)?

• May 16th 2006, 10:32 AM
earboth
Quote:

Originally Posted by ferdo
Ok, the question we got was to identify and explain one critical error in the factoring example.

this is the example:

X=X

X Exponent 2 = X Exponent 2

X Exponent 2 - X Exponent 2 = X Exponent 2 - X Exponent 2

X(X - X) = (X + X) (X - X)

X(X - X) = (X + X) (X - X)
-------- --------------
(X - X) (X - X)

X = (X + X)
X = 2X
If we let X = 1, then upon substitution we have
(1) = 2(1)
1 = 2

I think the problem lies in line 3 right side, (X + X) (X - X), should it be like the left side X(X - X)?

Hello,

if this means to be a division,

X(X - X) = (X + X) (X - X)
-------- --------------
(X - X) (X - X)

then you divided by (x-x) = 0 and that's not allowed.

Greetings

EB